The present invention relates to an electroactuator control device and to a method for controlling this control device.
The control device according to the present invention can be used advantageously, but need not be used exclusively, to control electroinjectors of an injection system for an internal combustion engine of the petrol, diesel, methane or LPG-operated type, to which the following description will make specific reference, without however detracting from general applicability.
In fact the control device according to the present invention can also be applied to any other type of electroactuator, such as solenoid valves of ABS devices and the like, and solenoid valves of variable phasing systems etc.
As is known, in order to control the electroinjectors of an injection system of an internal combustion engine, it is necessary to supply to each electroinjector a current, the development of which over a period of time comprises a section of fast increase, a section of slower increase, a section of decrease to a maintenance value, a section of oscillating amplitude around the maintenance value, and a section of decrease to a value of approximately zero.
In order to obtain this development over a period of time, at present control devices are used in which the electroinjectors are connected on the one hand to a low voltage supply source, and on the other hand to an earthing line, by means of a controlled electronic switch.
These control devices have the disadvantage that any short-circuit to earth of one of the terminals of any of the electroinjectors, caused for example by a loss of insulation in a wiring conductor of the electroinjectors themselves, and by the contact of this conductor with the vehicle bodywork, would damage definitively the electroinjector itself and/or the control device, thus making the vehicle stall, which is a decidedly dangerous situation when the vehicle is running.
In order to avoid this dangerous disadvantage, control devices for electroinjectors have been proposed which are connected on the one hand to earth, and on the other hand to an internal node of the control devices themselves, such that any short-circuit to earth of one of the terminals of the electroinjectors does not give rise to damage to the control device, and thus to stalling of the vehicle, but simply puts that individual electroinjector out of use, so that the vehicle can continue to run with one electroinjector short.
However these control devices have the disadvantage that their circuitry is complicated, they are costly, and also in general they do not make it possible to carry out simultaneous injections into different cylinders, which would however be necessary for example in cases in which control of injection of the engine requires multiple injections into each cylinder.